Starting next week, 40,000 U.S. Census Bureau workers will fan out across the U.S. to verify and update residents' addresses.

The verification of addresses is the most labor-intensive component of the bureau's preparation this year for the 2020 count, which starts next spring. The workers are known as "listers." They'll cover about a third of the nation's physical area.

In years past, listers walked every block of every street in the nation to make sure physical addresses matched those listed in government files.

For this census, workers are starting the verification process from their office computers.  Using aerial imagery, they're looking for blocks where there has been significant growth or decline. They'll then send listers to those blocks to check actual numbers.

The Census Bureau conducts a count of every U.S. resident every 10 years.

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